1. Field of the Invention
The present invention relates to a drum brake and, more particularly, to a cabling structure of a parking cable of the drum brake.
2. Description of the Prior Art
In the drum brake equipped with a parking brake of the prior art, a change of the direction of leading out the parking cable is conducted by guiding the single parking cable through a cable guide which is fixed on a backing plate or the like. This is accompanied by the slide or fold of the parking cable to cause a defect that the parking cable is liable to be broken. In view of the defect, there has been proposed a concept of changing the direction of leading out the parking cable by hinging a bell crank or a pulley to the backing plate.
However, the structure using the bell crank has a difficulty that the lever ratio fluctuates in accordance with the swinging motions of the bell crank when the parking brake is to be applied. On the other hand, the structure using the pulley, as disclosed in U.S. Pat. No. 3,245,501, has a difficulty that the lever ratio cannot be changed because a single parking cable is wound on the pulley.